close

Вход

Забыли?

вход по аккаунту

?

код для вставки
200517.fm Page 162 Friday, March 18, 2005 2:52 PM
2005
Pyridine derivatives
R 0380
Design of a Nonreductive Method for Chemoselective Cleavage of Hydrazines
the Presence of Unsaturations: Application to a Stereoconvergent Three17- 146 in
-Component Synthesis of (-)-Methyl Palustramate. — A three component
aza[4 + 2]cycloaddition/allylboration/retro-sulfinyl-ene reaction leads to various
cis-substituted piperidines in a highly regio- and stereoselective fashion. Unfortunately,
cleavage of the hydrazine bond without reduction of the C=C double bond is problematic. Only hydrazines bearing a -CH2-SiMe3 group are able to undergo successful conversion into the desired piperidines like (XIII) under mild acidic conditions. This route
is applied to a convergent asymmetric synthesis of the palustramate (XIV). Additionally, it is shown that the new, mild hydrazine cleavage is not limited to monocyclic
piperidine substrates of type (XII). Bicyclic derivatives such as the azaisoindole (XV)
can also undergo desired N-N fragmentation. — (TOURE, B. B.; HALL*, D. G.; J.
Org. Chem. 69 (2004) 24, 8429-8436; Dep. Chem., Gunning-Lemieux Chem. Cent.,
Univ. Alberta, Edmonton, Alberta T6G 2G2, Can.; Eng.) — Jannicke
200517.fm Page 163 Friday, March 18, 2005 2:52 PM
2005
Документ
Категория
Без категории
Просмотров
0
Размер файла
54 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа